The earliest parabolic trough system on the planet, Accurex. Much smaller than current technologies, it also covered more ground. These are turned downward so the tubes don’t break in the sun.

Screen grab from Google Maps of the Plataforma Solar de Almería. Clearly visible are several iterations of solar power tower, as well as parabolic trough and other technologies.

The Plataforma Solar de Almería is in southeastern Andalucía, Spain’s sun-drenched southermost autonomía, in an area called the Desierto de Tabernas, the only desert in Europe (Google Maps link). According to worldclimate.com data, Almería, the local provincial capital (provinces in Spain are roughly analogous to counties in the U.S.) receives 8.8″ of rain per year, the very definition of a desert. According to the PSA staff, the Tabernas desert has over 3000 hours of good solar insolation per year. Considering that 4350 hours per year are at night, that’s a truly remarkable amount of sunlight for such relatively northern latitudes (at 37°N, it is roughly equivalent to San Francisco or the Central Plains in the U.S.- you gotta love the jet stream!).

SSPS-CRS, the world’s first solar power tower facility, constructed in 1981.

While facilities such as the early Luz plants in Israel (Luz went bankrupt and reformed itself as the now-industry-leading BrightSource Energy some years later) and the many Kramer Junction SEGSs in the Mojave Desert were innovators in concentrating solar thermal technology, they really owe their root technologies to the PSA. The PSA built the world’s first concentrating solar power tower AND the world’s first parabolic trough designs in 1981, further refining both technolgies during the remainder of the 1980s.

Private enterprise has dominated such fields of technological innovation in the past few decades in the United States, but the PSA is fully funded by the Spanish Government, through its Centro de Investigaciones Energéticas, Medioambientales, y Tecnológicas (CIEMAT). It also collaborates with government research bodies from other European countries, notably Germany. Technologies are then leased or sold to private enterprises, through our tour guide was vague on fee structures and terms on such contracts.

Parts of the PSA seemed like a veritable solar graveyard, as old or abandoned technologies slowly bleach in the sun.

On to the technology! We got to view the world’s first solar power tower facility, the SSPS-CRS (the Small Solar Power System- Central Receiver System, weird that they gave it an English name and acronym), which amazingly was constructed over 30 years ago, in 1981. When used to generate power, it employed around 100 heliostats, each with an independent small PV cell to power their movement (check out the picture here), focusing their light on a 42m tall tower, creating a whopping 500kW of energy. In the intervening years, with its pioneering technology long eclipes, the SSPS-CRS has been used for fascinating research in the splitting of water and hydrocarbon molecules to generate free hydrogren atoms, with potential applications in artificial photosynthesis.

The CESA-I, from 1983, a more refined solar power tower facility which resembles the modern technologies of today.

A few years later in 1983, they upgraded this technology significantly, with the CESA I (I’m a bit ashamed to say I did not catch what this acronym stands for), a 84m tower with 300 heliostats, capable of generating 1.2MW. The CESA I bears much more resemblance to the towers which we know today, from plants in Spain, the United States, and elsewhere. [For especially nerdy readers who also can read Spanish, here’s a picture of the interpretive sign for the power towers.] Remarkably, it can generate temperatures of up to 1500°C (some 2700°F)! Compared to Ivanpah’s meager sounding 1050°F, this sounds very impressive. One would imagine that Ivanpah’s technology makes better use of the already high temperatures it has, such that temperatures hot enough to melt metal aren’t necessary (seriously, look at this picture).

Various iterations of the Stirling Engine, the oldest to the left and most recent to the right, a technology that has yet to prove commercially viable at utility-scale.

Solar power tower wasn’t the only technology on display at the PSA, though it was certainly the most impressive. Early incarnations of parabolic trough designs, much smaller (just a few feet across), and more heavily concentrated, so that almost no sunlight reached the ground, were scattered about the site (Spanish parabolic trough interpretive sign). The entire evolution of the Stirling engine was also visible, from a black dish to a curved mirror system. And all around, like a graveyard of solar technologies, were decommissioned panels, troughs, cells, dishes, and every other possible incarnation of solar energy technology.

And so it was a day at the Plataforma Solar de Almería to forget about politics for a minute, and simply enjoy the fascinating path of technological development over the past 30 years. The center focuses on technology, not siting, and thus is able to stay above the political fray. And perhaps the visit also offered some hope- if humanity, when properly motivated, can devise such ingenious and seemingly miraculous ways to transform sunlight into energy, surely we can find appropriate places to site such technologies. I left feeling optimistic, that utility-scale solar, if its siting and impacts are properly considered, could be a force for good in our future energy mix.

Through a bit of research serendipity, my trip to Andalucía this summer happened to coincide with a field studies program from Arizona State University’s Consortium for Science, Policy & Outcomes and Global Technology and Development Program. They had thirty enthusiastic undergraduate and graduate students, who were touring many of the facilities I was interested in visiting, and were gracious enough to let me tag along. (Huge thanks are in order to Sharlissa Moore, a brilliant doctoral candidate at ASU who will be spending the next four months in Rabat, Morocco, doing field work for her dissertation on the DESERTEC project, amongst other solar intiatives in the MENA area).